Fructose may increase cravings for high-calorie foods, according to a new study.
Researchers at the University of Southern California got24 volunteers to consume a sugary drink sweetened with fructose - the sugar found in fruit - on one day and glucose on another day.
Compared with glucose, the fructose drink led to more hunger and desire for treats such as biscuits and sweets, suggesting that different sugars may affect us differently.
The participants were given a sweetened, cherry-flavoured drink but were not told what was in it - fructose or glucose.
Shortly afterwards, they were asked to rate how hungry they were. They then underwent brain scans while being shown pictures of foods such as biscuits, sweets, burgers and pizza, as well as some 'neutral' photographs of buildings.
Some days later, the same volunteers came in again and repeated the experiment. The only difference was the type of sweetener added to their cherry drink.
The brain scans showed that people responded more strongly to photos of food if they had been drinking fructose, rather than glucose. Some of the subjectsalso reported more food cravings for treats shortly after consuming fructose.
Although fructose and glucose contain the same energy or calories, the body breaks the sugars down in different ways, and the researchers believe this might explain their findings.
The study was published in the PNAS journal.